The present invention relates to aircraft and, more particularly, to aircraft having a pivotable powerplant.
Engines or powerplants of most conventional aircraft are fixedly mounted within an airframe of the aircraft, on the tail of the aircraft, or on aircraft wings. Fixedly mounting powerplants in these locations has various drawbacks including challenges related to aircraft control and installation, inspection, repair, and removal of the powerplants. It is often desirable to vector exhaust from powerplants to provide thrust at various angles with respect to the airframe of the aircraft. For aircraft having one or more powerplants mounted within the airframe, vectoring is usually accomplished by deflecting powerplant exhaust to exit the aircraft at angles between about horizontally rearward and vertically downward with respect to the airframe. For example, some conventional aircraft have vanes connected to the airframe downstream of the powerplant for selectively deflecting exhaust produced by the airframe downward to various degrees with respect to the airframe. Deflecting powerplant exhaust to provide thrust in various directions is generally inefficient because energy of the exhaust is reduced when it is deflected thereby decreasing thrust produced by the aircraft.
For vectoring exhaust from powerplants mounted on the wings to exit the aircraft at various angles, the wings of some conventional aircraft can rotate with respect to the airframe. When the wings of these aircraft are rotated, the wings and powerplants mounted thereon rotate together. One drawback of these aircraft is an inability to orient the wings in their forward flight or home position while vectoring exhaust to exit the aircraft at an angle with respect to the airframe below horizontally rearward. Although it is sometimes desirable to rotate the wings and powerplants of such aircraft together, for example, for flying vertically, it would also be advantageous at times to be able to selectively vector the exhaust to exit the aircraft at angles above and below horizontally rearward while keeping the wings in their home position. For example, as will be appreciated by those skilled in the art, vectoring exhaust to exit the aircraft at angles above and below horizontally rearward while maintaining the wings in their home position could facilitate many intermediate flight maneuvers between forward flight and vertical flight. Further, vectoring exhaust to exit the aircraft at angles other than horizontally rearward while keeping the wings in a home position can improve landing and take off, as described in the Detailed Description of the Invention section below.
Installation, inspection, repair, and removal of powerplants are often challenging. Installing and repairing powerplants mounted in the fuselage require accessing and working within a usually close-quartered interior of the fuselage. The need to access and work within the fuselage increases the complexity and cost of installing, inspecting, maintaining, and removing the powerplant. For most conventional aircraft designs, installing and removing and, sometimes, inspecting and repairing powerplants requires using a boom or crane to hold the engine at or adjacent its position on the aircraft, far above ground level. Personnel must also climb or be lifted to the powerplant position for installation, inspection, repair, and removal. Aircraft assembly and maintenance would be improved if the powerplant position on the aircraft was more easily accessed from the ground.
Further, conventional aircraft having a powerplant mounted within its fuselage require ancillary structure sometimes including heavy ductwork for channeling the exhaust to an orifice through which the exhaust exits the aircraft. These aircraft also have heat and acoustic barriers to insulate the fuselage, cockpit, storage bays, and/or other internal structures from the powerplant. Some or all of these barriers are not needed when the powerplant is mounted outside of the fuselage.